Press brake assemblies commonly include an upper table and a lower table. The upper table may be equipped to move vertically with respect to the lower table. Various forming tools may be mounted to the tables such that when the tables are brought together, the tools may bend or impress a workpiece, such as a piece of sheet metal, placed therebetween. Typically, the upper table will couple with male forming tools, such as press brake and punch tools, and the bottom table will couple with female forming tools, such as dies. In order to perform a variety of forming operations, differently shaped forming tools must be used. Thus, it is often necessary to exchange various forming tools within both the upper table and lower table.
Because the forming tools mounted in the lower table are supported from below, they may be substituted with relative ease. The forming tools mounted to the upper table, however, are suspended from above, usually held in place by a clamping mechanism that clamps all of the forming tools simultaneously. Upon loosening, unlocking, or releasing the clamping mechanism, the forming tools mounted to the upper table may be removed by sliding the tools horizontally to an open end of the upper table, or in some instances, by removing the tools vertically. Horizontal exchange of the forming tools can be cumbersome due to the proximity of the forming tools with respect to one another in the upper table, often necessitating the removal of each tool mounted within the upper table when only one tool is being exchanged. Neighboring clamps may also interfere with horizontal removal of the tools.
Vertical removal and insertion of the forming tools may not improve the exchange process due to the safety risks associated with handling the often heavy forming tools. In particular, loosening the clamping mechanism of the upper table may result in one or more tools falling and injuring a press brake operator.
To prevent the forming tools from accidentally falling from the upper table of a press brake assembly, several safety mechanisms have been developed. One such mechanism may involve a safety tang that protrudes laterally from a surface of the forming tool. Such a safety tang may be shifted into a complementary groove defined by a tool holder in the upper table, thereby securing the tool to the holder until the tool is clamped. This mechanism is problematic, however, because of the manipulation required of the operator to actuate the safety mechanism, which is often concealed by the holder, and therefore inaccessible to the operator. Securing such tools within an unclamped holder remains difficult and unsafe.
Thus, there exists a need for improved mechanisms used to secure forming tools to the upper table of a press brake assembly or similar apparatus while the clamping mechanism of such an assembly is disengaged, such that heavy forming tools can be quickly exchanged without the risk of accidentally falling.